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- Can houseplants improve indoor air quality?
- Cautious garden banter
- Giving Thanks for Gardening
- Food for thought – Insects on the menu
- Be on the lookout for new uninvited house guest.
- Holes in trees – wood borer or woodpecker?
- Little bulbs yield major reward in spring
- Trial Plants winners for 2016
- Yellowjackets – insects with attitude
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The Homeowners Column
Sometimes evergreens aren’t evergreen
Extension Educator, Horticulture
They spend the summer disguised as evergreens. They have the distinctive narrow needled leaves we identify with evergreens of spruce, pines, and yews. Then as autumn rolls around some trees give up their masquerade and surrender their leaves to the season. The needles turn rust colored and engage in a diving contest with the maples. Will we all dive together in a cannonball? Or perhaps this time a more refined 180 degree flip?
I have heard horror stories where people thought their bald cypress was dead and cut it down since all the needles fell off in October. We have a few deciduous conifers that grow in our area and are worth adding to your landscape.
Bald Cypress, Taxodium distichum, is native to moist areas of Illinois and the US. Trees are distinctly pyramidal and reach 70-80 feet tall and 20 to 30 feet wide. Mature trees are majestic cathedral spires. Their buttressed base gives them tremendous tolerance to high winds. In other words it's hard to knock them over. Bald cypress do their best growth on moist to wet areas with acidic soil. They can develop iron deficiency which causes the leaves to turn yellow in high pH soils. In wet areas bald cypress is a bit risqué as it shows its characteristic knobby knees. If that is too wild for you, don't worry, knees don't develop in drier landscape areas. In fall the needles turn an orange brown color before their dive to the ground.
Dawn Redwood, Metasequoia glyptostroboides, has been around for some 100 million years. Fossil records show dawn redwood was once native to North America. As the climate changed, the trees continued to grow only in remote locations in China. Some 50 million years later dawn redwood returned to North America with a little help from its friends. In 1947 The Arnold Arboretum sent plant hunters to China to collect seeds. Arboreta love to share seeds with other arboreta. After years of sharing and propagating, dawn redwood is available for purchase in some garden centers.
It's a statuesque pyramidal tree growing 70 to 80 feet tall with a 25 foot spread. Dawn redwoods are very fast growing. They can reach 50 feet tall in 15 to 20 years. The bright green flat needles turn rusty brown in fall before the branchlets drop. Dawn redwood has few insect and disease problems, but Japanese beetles will eat the leaves. Since it's been hanging around on earth for 100 million years, it must be pretty adaptable. It's easy to transplant and grows best in moist, well-drained, slightly acid soil and grows well along ponds or streams.
The beautiful shredding orange bark is similar to bald cypress. The trees have distinctive arm pits where the branches attach to the main trunk.
There is a lovely large labeled dawn redwood near the northeast corner of Lincoln Avenue residence Hall on U of I campus. While you are wandering campus, check out another elegant deciduous conifer eastern larch, Larix decidua, in Illini Grove. Several larch line Lincoln Avenue.
All three of these tree species are unrivaled for large spaces in a park or large yard. Several can be grouped as a screen or along driveways. So don't fret when your conifer loses its leaves in fall, it might just be doing what comes naturally.
Curious about honey bees and stinging insects?
Join us for a two session distance learning program taught by Dr. Stu Jacobson of University of Illinois on Tuesday, November 14, 1 to 3 pm and Wednesday, November 15, 10 am to Noon. Discover basic honey bee biology and behavior, pollination, importance of native bees, behavioral differences between bees and wasps, and management options. There is no charge, but please call the Extension office at 217-333-7672 to register.